North American Ecosystems and tools for their restoration

Ecosystems

Biome or ecosystem types
Whittaker 1975

•          1. Tropical rain forests

•          2. Tropical seasonal forests

•          3. Temperate rain forests

•          4. Temperate deciduous forests

•          5.  Temperate evergreen forests

•          6.  Taiga (subarctic-subalpine needle leaved forests)

•          7. Elfinwoods

•          8. Tropical broadleaf woodlands

•          9. Thornwoods

•          10. Temperate woodlands

•          11. Temperate shrublands

•          12. Savannas

•          13. Temperate grasslands

•          14. Alpine shrublands

•          15. Alpine grasslands

•          16. Tundras

•          17. Warm semidesert scrub

•          18. Cool semideserts

•          19. Arctic-alpine semideserts

•          20. True deserts (primarily sub-tropical)

•          21. Arctic-alpine deserts

                Hydric Communities

•          22. Cool temperate bogs

•          23. Tropical freshwater swamp forests

•          24. Temperate freshwater swamp forests

•          25. Mangrove swamps (tropical)

•          26. Salt marshes of temperate coasts

•          27. Freshwater lentic communities (lakes and ponds)

•          28. Freshwater lotic communities (streams)

                Littoral communities (where land meets the sea)

•          29. Marine rocky shores

•          30. Marine sandy beaches

•          31. Marine mud flats

•          32. Coral reefs

•          33. Marine surface pelagic communities (light)

•          34. Marine deep pelagic communities (lacking light)

•          35. Continental shelf benthos

•          36. Deep ocean benthos

 

North American Ecosystem Types

•          Coniferous forest

•          Eastern deciduous

•          Western deciduous

•          Woodlands

•          Desert

•          Shrublands

•          Meadowlands

•          Glades

•          Grasslands

•          Prairies

•          Sand dunes

•          Floodplain forest

•          Bogs and fens

•          Swamp forest

•          Riparian forest, woodlands

•          Shrub swamps

•          Non-estuarine marsh

•          Wet prairie, grassland

•          Vernal pools

•          Mangroves

•          Estuarine marsh

 

Eco-region mapping

•          Kόchler map of potential natural vegetation of North America

•          Bailey’s eco-regions of the United States

 

Restoration Obstacles
 and Opportunities
in Different Ecosystems

•          What is restoration?

•          Installing vegetation, or encouraging it

•          Depending on vegetation to accumulate the necessities of a functional ecosystem (organic matter, water, nutrients, soil)

•          Renewing natural processes that occur in functioning ecosystems.

•          Providing ecosystem functions that have been curtailed (hydrology, water quality, habitat)

 

Grasslands and Prairies

•          Obstacles

–        Grazing

–        Fragmentation

–        Water supply only seasonally adequate

–        Fire-adapted invasives

–        Modification of fire regimes

–        Encroachment by woody species

•          Opportunities

–        Hardy, adapted natives; many of them grasses

–        Native graminoids fire adapted, invasive woody species not.

–        Some refugia exist

–        Seeding works in these environments.

 

Oak Woodlands and Savannas

•          Obstacles

–        Encroachment by conifers

–        Juniper advance in southwest and midwest

–        Encroachment by shrubby understory species in midwest

–        Poor recruitment

–        Grazing

–        Modification of fire regimes

•          Opportunities

–        Fire adaptation

–        Very stress-tolerant dominants

–        Landscape structure creates fire-safe islands

–        Rocky landscapes create refugia

–        Good survival of seedlings

 

Freshwater Wetlands

•          Obstacles

–        Adequate moisture and light make habitat invasion-prone

–        Openness of system makes it invasion-prone

–        Nasty suite of invasives: reed canarygrass, knotweeds, Phragmites.

–        Seeding is not generally effective as the primary mode of installing plant materials.

–        Herbivores

•          Opportunities

–        Adequate moisture

–        Plantings installed during the wet season do not need additional water

–        Abundant sunlight in many systems

–        Terrestrial invasives excluded

–        Live stakes work

 

Coastal Wetlands

•          Obstacles

–        Salt-affected system; fewer adapted species

–        Salt marshes are patchy systems with some areas that are very restrictive to plant growth.

–        Long-inundation areas

–        High marsh can become hypersaline

–        Geese

–        Tides: access to marsh is time-limited.

•          Opportunities

–        Native species are well-adapted to the unique stresses in this environment.

–        Salt-affected systems have limited set of invasives

–        Tides moderate salinity and provide water.

–        Dominant species are clonal, perennial graminoids that grow and spread rapidly.

–        Brackish areas may have very fast growth

 

Marine Systems

•          Obstacles

–        Populations of marine plants tend to appear and disappear.

–        Water clarity is critical; sediment and nutrients can decrease sunlight penetration.

–        Installation often requires diving.

–        Algal culturing requires technical competence.

–        Grazers and epiphytes inhibit growth

–        Minus tides can create extreme stress

•          Opportunities

–        Eelgrass is easy to salvage and transplant.

–        Minus tides in summer allow transplanting without diving.

–        Environmental conditions tend to be very stable.

–        Growth is fast; algal growth is very fast

 

Arctic

•          Obstacles

–        Short growing season, cold, wind, little sun

–        Stressful conditions (flooded sites, xeric sites)

–        Non-Arctic species will not persist

–        Growth is very slow, ecosystem recovery slow

–        Melting of ice-rich soils precludes any restoration

–        Surface modification may result in melting of soils

–        Nitrogen-poor environments

•          Opportunities

–        Well-adapted native species

–        Native graminoids will spread

–        Patchy environments have some oases.

–        Some wet sites may be more amendable to restoration

–        Money available from oil company settlements

 

Alpine

•          Obstacles

–        Cold, wind, scouring by windborne ice and sand particles

–        Big diurnal temperature swings, freeze-thaw cycles and soil creep

–        Patchy environment

–        Few adapted species

–        Slow growth

–        Slow ecosystem rebound from disturbance

–        Genetic fidelity important

·         Opportunities

–        Snow cover

–        Well-adapted natives

–        Growing season conditions may allow more production than Arctic

–        Alpine and subalpine plants can be grown in greenhouses at lower elevation

–         

Aridlands

•          Obstacles

–        Lack of moisture

–        Annual moisture not predictable in warm deserts

–        Alien grasses introduced for grazing

–        Increased fire frequency

–        Cheatgrass

–        Grazing

–        Vastness, isolation

•          Opportunities

–        Seeding works

–        Annual moisture predictable in cool deserts

–        Natives well-adapted to low moisture, and some to high salinity

–        Plants stress-tolerators

–        Just add water

Thornscrub

•          Obstacles

–        Very fragmented; limited seedbank

–        Some thornscrub species grow slowly

–        Planting must occur at end of wet season; this leaves only a small window of time to plant.

–        Acreage large; land valuable for other purposes

–        Over 150 woody species and 100 grasses in S. Texas; plant material hard to get.

•          Opportunities

–        Some species grow fast

–        Some species may be seeded

–        Most are woody and very stress-tolerant

–        System is shrubby and does not normally burn.

–        Since much restoration is re-converting farmland, agricultural techniques may be used

–        Valuable wildlife land

Tropical Moist Forest

•          Obstacles

–        Continued conversion of forest to sunny pasture

–        Forest seeds large, with short dispersal potential

–        Aggressive introduced grasses

–        Fire

–        Fragmentation resulting in less regional moisture and more fire

–        Harsh sunny conditions for shade adapted seedlings

•          Opportunities

–        Fast-growing trees, some wind-borne seeds

–        Many species

–        Adequate moisture

–        Animal dispersers

–        Perch trees

 

Tropical Dry Forest

•          Obstacles

–        Lack of shade

–        Introduction of fire into non-fire-adapted systems

–        Introduced invasives (in Hawai’i,  Pennisetum setaceum, candelabra grass)

–        Grazing

–        Pigs

•          Opportunities

–        Well-adapted native species

–        Isolated areas protected from fire

–        Well-established natives at higher elevations

–        Long growing season, seasonal rain.

–         

Old Growth Forest

•          Obstacles

–        Commercial value of plantation forests

–        Historical fire management

–        Heavy understory growth

–        Requires a long view

–        Requires medium-sized to large parcels

·         Opportunities

–        Requires little other than selective harvest

–        Some harvested materials can be extracted to finance the restoration

–        Some old growth survives because it is in  inaccessible areas.

–        Areas around old growth can be managed to become old growth

 

River Restoration

•          Obstacles

–        Requires a coordinated effort, including watershed, riparian and instream scales.

–        Permitting is required

–        Heavy equipment and transport of materials required for instream work

–        High-energy systems may disturb restored sites.

•          Opportunities

–        Work at watershed or riparian scale may result in restoration at lower scales because of modified sediment and water flows.

–        Riparian restoration is done in a system in which establishment and growth is facilitated

–        Lots of salmon recovery funding available

 

Freshwater Tidal Systems

•          Obstacles

–        Very fragmented

–        Less of this system remains than most others

–        River systems now dammed and diked; no more floods like historical ones.

–        Heavily logged and converted to agriculture

–        Diking, tide-gates, culverts, roads, drains

–        Land subsidence

•          Opportunities

–        Some of system remains in family farms, wildlife areas, outside of dikes

–        Legacy wood exists in some areas now used as pasture.

–        Land conservancies have purchased some better sites

–        Salmon recovery money has enabled purchase and protection

–        Fragmentation may make sites less profitable for logging.